The present invention relates to a method for firmly-bonded connection of an electronic component to a substrate, and to an arrangement that can be obtained in said method.
WO 2011/009597 A1 discloses a method for making firmly-bonded connection of an electronic component to a substrate, comprising a) providing an electronic component having a first surface to be connected and a substrate having a second surface to be connected, b) applying a solder paste to at least one of the surfaces to be connected, c) arranging the electronic component and the substrate appropriately such that the first surface of the electronic component to be connected and the second surface of the substrate to be connected contact each other by the solder paste, and d) soldering the arrangement from c) in order to generate a firmly-bonded connection between the electronic component and the substrate. The thickness of the applied layer of solder paste is at least 20 μm. The solder paste used in the method contains (i) 10-30% by weight (percent by weight) copper particles, (ii) 60-80% by weight particles made of at least one substance selected from the group consisting of tin and tin-copper alloys, and (iii) 3-30% by weight solder flux, wherein the mean particle diameter of the copper particles and of the particles made of at least one substance selected from the group consisting of tin and tin-copper alloys is ≤15 μm.
In the article “Standard-Reflowlöten für Anwendungen bis 300° C.—ein Widerspruch? Ergebnisse aus dem Verbundprojekt HotPowCon” published in DVS-Berichte, Elektronische Baugruppen and Leiterplatten EBL 2014 (ISBN 978-3-87155-573-2), A. Fix et al. report on a soldering method that utilizes two pastes that are applied separately, i.e., one paste containing copper particles and one paste containing a soldering metal particle.
The soldering connections produced according to the method according to WO 2011/009597 A1 attain good strength, but have proven to be improvable with respect to homogeneity and absence of hollow spaces and, ultimately, also with respect to reliability, in particular under high temperature conditions in the range of, for example, 250 to 300° C. during the development work on the present invention.